fix callback URL to use configurable public base

Separate callback URL generation from LISTEN_ADDR by introducing CALLBACK_BASE_URL with a localhost default for local development.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/config/config.go

@@ -36,6 +36,9 @@ type Config struct {
 
 	// Server
 	ListenAddr string
+
+	// Public callback base URL for OpenClaw callbacks
+	CallbackBaseURL string
 }
 
 // Load reads .env (if present) and populates Config from environment variables.
@@ -59,6 +62,7 @@ func Load() (*Config, error) {
 		SystemEmail:         os.Getenv("SYSTEM_EMAIL"),
 		IMAPProxyURL:        os.Getenv("IMAP_PROXY_URL"),
 		ListenAddr:          os.Getenv("LISTEN_ADDR"),
+		CallbackBaseURL:     os.Getenv("CALLBACK_BASE_URL"),
 	}
 
 	if raw := os.Getenv("WHITELIST_EMAILS"); raw != "" {
@@ -72,6 +76,9 @@ func Load() (*Config, error) {
 	if cfg.ListenAddr == "" {
 		cfg.ListenAddr = ":8080"
 	}
+	if cfg.CallbackBaseURL == "" {
+		cfg.CallbackBaseURL = "http://localhost"
+	}
 
 	if err := cfg.validate(); err != nil {
 		return nil, err

internal/config/config_test.go

@@ -0,0 +1,50 @@
+package config
+
+import "testing"
+
+func setRequiredEnv(t *testing.T) {
+	t.Helper()
+	t.Setenv("IMAP_HOST", "imap.example.com")
+	t.Setenv("IMAP_PORT", "993")
+	t.Setenv("IMAP_USER", "u")
+	t.Setenv("IMAP_PASS", "p")
+	t.Setenv("SMTP_HOST", "smtp.example.com")
+	t.Setenv("SMTP_PORT", "587")
+	t.Setenv("SMTP_USER", "u")
+	t.Setenv("SMTP_PASS", "p")
+	t.Setenv("OPENCLAW_URL", "http://openclaw.local")
+	t.Setenv("BRIDGE_CALLBACK_TOKEN", "token")
+	t.Setenv("SYSTEM_EMAIL", "system@example.com")
+	t.Setenv("LISTEN_ADDR", ":8080")
+	t.Setenv("WHITELIST_EMAILS", "")
+	t.Setenv("IMAP_PROXY_URL", "")
+	t.Setenv("OPENCLAW_API_KEY", "")
+}
+
+func TestLoad_DefaultCallbackBaseURL_WhenUnset(t *testing.T) {
+	setRequiredEnv(t)
+	t.Setenv("CALLBACK_BASE_URL", "")
+
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("load config: %v", err)
+	}
+
+	if cfg.CallbackBaseURL != "http://localhost" {
+		t.Fatalf("expected default callback base URL http://localhost, got %q", cfg.CallbackBaseURL)
+	}
+}
+
+func TestLoad_UsesCallbackBaseURL_WhenSet(t *testing.T) {
+	setRequiredEnv(t)
+	t.Setenv("CALLBACK_BASE_URL", "https://bridge.example.com")
+
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("load config: %v", err)
+	}
+
+	if cfg.CallbackBaseURL != "https://bridge.example.com" {
+		t.Fatalf("expected callback base URL from env, got %q", cfg.CallbackBaseURL)
+	}
+}